Jens G. Rohwer – författare

This volume - the first of this series dealing with angiosperms - comprises the treatments of 73 families, representing three major blocks of the dicotyledons: magnoliids, centrosperms, and hamamelids. These blocks are generally recognized as subclasses in modern textbooks and works of reference. We consider them a convenient means for structuring the hundreds of di­ cotyledon families, but are far from taking them at face value for biological, let alone mono­ phyletic entities. Angiosperm taxa above the rank of family are little consolidated, as is easily seen when comparing various modern classifications. Genera and families, in contrast, are comparatively stable units -and they are important in practical terms. The genus is the taxon most frequently recognized as a distinct entity even by the layman, and generic names provide the key to all in­ formation available about plants. The family is, as a rule, homogeneous enough to conve­ niently summarize biological information, yet comprehensive enough to avoid excessive re­ dundance. The emphasis in this series is, therefore, primarily on families and genera.

This new encyclopaedia, the second volume of which is presented here, offers access to the diversity of ferns and seed plants, the most imrtant groups of green land plants. Available information of general and systematic relevance is synthesized at the level of families. Evidence from virtually all disciplines important to modern taxonomy makes the work a most valuable source of reference not only for taxonomists, but for all who are interested in the various aspects of plant diversity. A revised classification includes a complete inventory of genera along with their diagnostic features, keys for identification, and references to the literature.